The wearable interaction device is one of the most prospective fields which the international companies are enthusiastically lay out the plan for after the development of the smart phone. The head mounted display (HMD) is one of the key devices in this field. The head mounted displays can be classified into immersion-type head mounted displays and see-through-type head mounted displays. By using the immersion-type head mounted display, the user cannot perceive the external environment and it is necessary to use an external camera to shoot the external images and to transmit the shot images to the display. By using the see-through-type head mounted display, the user can perceive both of the physical object in the external environment and the virtual images.
Although the augmented reality interaction system mainly based on the see-through-type head mounted display possesses relatively high sense of reality, the requirements for composing the real image and the virtual image is relatively high. The common issues of the see-through-type head mounted display comprises correction of the eye position, mutual interference between the real image and the virtual image and the erroneous shielding between the real image and the virtual image. Hence, the use of the see-through-type head mounted display in the augmented reality interaction system confronts a lot of difficult and complicated issues. Therefore, the see-through-type head mounted display is not as widely applicable as the immersion-type head mounted display.